He is older than me, he has a corporate job running a medium size company. He discovered Bitcoin, because of me. He put more money into BTC than me, he supposed to be the smart one...
Today, he just sent me a message saying that he is worry because of the Quantum computer and a link to this tweet: https://x.com/mreiffy/status/2038878566796988776
Please, give me your best answer to help him understand how BTC will manage this change in the future.
The Google paper says:
Google's current flagship Willow processor has something like 105 qubits.
I'm not knowledgeable enough to tell your brother when quantum computers will pose a real threat to bitcoin keys, but I don't think it's something that needs to cause him sleepless nights.
Put more bluntly:
source
Additionally, Bitcoiners have a number of good options for mitigating quantum risks. Casey Rodarmor actually proposed a pretty cool solution (#1445101). But there's lots of others, including BIP 360. Some of these are getting close to being ready to implement (if people want to do it).
https://twiiit.com/_jonasschnelli_/status/2038864081730646414
Tell him to ask his bank how he's going to resolve this.
😂😂😂😂😂😂😂😂😂😂
Tell your brother to worry more about the current government money system we live under, rather than quantum computers that aren't yet operational and are destroying wallets.
I think you should just study more and work less. That way, you’ll finally get to grips with Bitcoin, and then you can carry on working and building your wealth, without worrying about the news you see on X.
https://twiiit.com/mreiffy/status/2038878566796988776
The short version for your brother: we have time, and there's a plan.
Where quantum actually stands
The paper being cited claims a theoretical attack in minutes with ~500k physical qubits. Current state of the art is roughly 1,000–2,000 noisy qubits. The gap between where we are and a cryptographically-relevant quantum computer is likely a decade or more, by most serious estimates.
What Bitcoin would actually need to change
Only ECDSA (the signature scheme) is broken by Shor's algorithm. The hash functions (SHA-256, RIPEMD-160) are only weakened by Grover's algorithm — it's not a break, just a speed-up. Most Bitcoin held in standard wallets where the public key isn't exposed on-chain is behind a hash and therefore has two layers of protection.
Bitcoin's upgrade path
Post-quantum work is already underway. The most relevant proposal is P2QRH (Pay to Quantum Resistant Hash) — a proposed soft fork to add a quantum-resistant signature scheme alongside ECDSA. This follows the same upgrade pattern as Taproot and SegWit. Bitcoin can migrate. It just needs consensus and time, and we have both.
The practical takeaway
Tell your brother: if/when quantum becomes a real threat, the first institutions to panic will be banks and government bond markets — their entire infrastructure runs on RSA and TLS, all broken by the same attack. Bitcoin has a defined community process to respond. The legacy system doesn't move nearly as fast.
Self-custody with modern wallet types (P2WPKH, P2TR) is already in better shape than most assume.